New research from AllerGen’s CHILD Cohort Study has found that babies sleep less at three months of age if their mothers do not have a university degree, experienced depression during pregnancy or had an emergency cesarean-section delivery.

“Sleep affects a baby’s growth, learning and emotional development, and is one of the most common concerns of new parents,” says AllerGen investigator Dr. Piush Mandhane (University of Alberta), one of the study’s lead authors and site leader for the Edmonton site of CHILD.

“While earlier research has linked a mother’s socioeconomic status, including level of education, to shorter infant sleep duration, we have not really understood the factors at play. Our study revealed that 30% of the effect of maternal education on infant sleep duration is actually mediated by a mother’s prenatal depression, as well as the type of delivery.”

There are several possible explanations for the association between maternal depression and infant sleep: “Mothers in distress tend to have sleep problems during pregnancy, which can be ‘transmitted’ to the fetus via the mother’s circadian clock and melatonin levels,” observes AllerGen investigator and co-lead author Dr. Anita Kozyrskyj (University of Alberta).

“Maternal depression and emergency cesarean section also both lead to elevated free cortisol levels, which, in turn, may cause an exaggerated stress response in infants that negatively impacts their sleep.”

“Our study suggests that prenatal depression and birth mode are potential targets for healthcare professionals and policy makers to improve infant sleep duration,” adds first author Brittany Matenchuk, an AllerGen trainee. “Mothers who experience prenatal depression or an emergency cesarean delivery may benefit from support so that infant sleep problems do not persist into childhood.”

The study, published in Sleep Medicine, analyzed data from 619 infants and their mothers participating in the CHILD Cohort Study.